Automatic balancing device for centrifugal pumps and the like.



I. A. GRIESSMANN. AUTOMATIG BALANCING DEVICE FOR GENTRIFUGAL PUMPS ANDTHE LIKE.

APPLICATION FILED APR.23, 1908.

898,462. Patented Sept. 15,1908.

.W/ TIVESSAFS 40. KM w wf p construction of m FRANZ Anne GRIESSM'ANN, orBeams, GERMANY.

' auroiii'ric harmonic nnvrcis To all whom it may camera.-

Be it known that I, FRANZ Aano Gaines MANN, subject of Germany, residingat Berlin, Germany, have invented new and useful Improvements inAutomatic alancin Devices for Centrifugal Pumps and the Li e, of

which the followin is a specification.

My invention relates to im rovements in automatic balancing devicesv orhigh pres; sure centrifugal pumps, steam turbines, and the like. I f

In the accompanying drawing Figure 1 is a longitudinal section throuhone form ofnew baancing device. Figs. 2, 3 and 4 are like views ofmodifications.

n machinery of the class mentioned it has been the practice to overcomethe endlong thrust or axial pressure of theshaft by means i ofbalancing-pistons, which run with but slight play ina suitablyconstructed part ofthe casin Such a iston exerts a constant ush on t eshaft. ince, however, the end ong thrust in a steam. turbine,centrifugal p'ur'n and the like, can onlybe approximately calcu 'a'tedbeforehand, andsince the thrust,

' owing to internal wear and tear in the machine, alters during working,it is desirable to overcome such thrust 1n some manner which permits ofbalancing of the forces within certain limits. The resistance,therefore, must be greater or smaller, as there is greater or lessendlong thrust of the machine.

According to my invention I attain this by I i inounting on the shaftwhose endlong thrust is to be balanced, a rotating -member within achamber closed with the aid of narrow throttling fissures, in suchmanner that on I shifting of theshaft, owing to the changingendlongthrust, it causes increased resistance to the flow of thepressure agent and thus a ressure directed counter tothe shiftihg motionof the shaft and corresponding thereto.

Four different forms of constructions of the invention are illustratedin the drawing:

The pist n 0, runs with the usual slight radial ay of from 0.1 to 0.2mm. in a suit ably s aped part of the stationary casing. To the faces 0the piston there are presented two fixed walls, between which the istonhas so much axial clearance as the mem ers in the interior of themachine, such as the wheels of a centrifugal ,pum demand, if wear andtear of these mem ers by friction against each other is to be avoided.In the case of a centrifugal ump this clearance would, as

Specification'o! Letters Patent. Application filed April '23, 1908.Serial No. 428,770.

shifting OOOUI'TlDgf duce son CENTBIFUGLL PUMPS AND THE Lnr'e.

@atented Sept. 15,1908.

when the iston is in its middle position there woul be an axial distanceof from 2 to 3mm. between it and. each fixed wall. In

Fi s. 1 and 2 the extent of endlongthmstpos' 9 A sib e is limited on thepressure side by outwardly located facings and on the free side byinwardly located facing's; while in the constructions shown in Fi 's. 3and 4,- on

to the rig t or to the left the entire face 0 the piston bears againstthe .res ective fixed wall. In front or behind the ba ancing-piston, a,throttling-fissures, b, are provided, formed b the shaft, or a collaronit, running with tli e'small pla of 0.1 to 0.2 mm. in a correspondingfixed caring part.

Egg. 1, the hen the Referring more particularly to, manner of working isas follows. piston, a, is in its central position there prevails in thechamber, A, a pressure, p, and in the space, B, in front of the piston,a, a pres-- sure, which is less-owing1 to the fal of pressure in thefissure, b; in t e space, C, be-

ind the-piston, a, there prevails the outside pressure, p since with thefacings at the 1 mean distance of from 2 to 3. mm. at, d, there will beno accnmulation of ressure in the s ace 0, and the normal end on thrustprouced by the pump is balance in the central position of the piston.-Should, now, for any of the reasons mentioned, the endlong thrust ofthe machine acting in the direction of the arrow increase there willresult a mo tion of the Shaft and t us of the piston toward the left.The facing s ,c, thus approach each other, andas they offer increasedresistance to the work agent flowing through, they cause accumu ation ofpressure in the space, B.' Since p increases, therefore, the totalpressure exercised on the, piston, 01., is increased and the endlongthrust of the ma.-

chine 'isbalanced again. Should the endlong thrust acting in t cdirection of the arrow diminish, the shaft will be shifted to the rightby the piston and there will be a resistance to flow at, d, in the; samemanner as there was such before at, c. In this manner the're will be anincrease of pressure caused in the s ace, 0, so that the piston, a,, byreason of t e counter-pressure-on its right-hand face will now only beable to balance a smaller total pressure than when it wasin the central(position. The endlong thrusts proby the piston and the machine are thusalso againe ual. x

The manner 0 working of the automatic balancing-piston shown in Fi 3,which has no facings, differs from the a eve-described only in as muchas the pressures occuring in the spaces, B, and, 'C, after motion of thepiston, 11, are not constant over theentire area of the piston, butalter according to some law, viz. decrease from within outward,

' or vice versa;

The mode of operation of the construction shown in Fig. 2, with athrottling fissure located rearward of the ist'on, is asfollows.

During normal endlong t rust of the machine, 1

that is, when the pistonis in its central position, there exists onstheface of the piston, (1,

turned toward the pressure chamber, A, a

pressure, p, which in consequence of the imited play at, 6, 1n thespace, 0, falls to p p and, owing to the fissure, b, is finally reducedto the outside pressure, p". If the pressure of the machine acting inthegdirection of the arrow increases,'there results a motion of theshaft toward the left and the fissure at, 0, being reduced ofiersresistance to' a the agent flowing through, so that the 001mter-pressure on the piston, a, which is'conditioned by the tension inthe space,' (3,

becomes lower. The decrease of pressure on the right hand face of thepiston must be i such that the piston again balances the invwill shifttowardthe ri ht.

proach of the facings at, resistance will e. offered to the flow of theagent, so that thecreased endlongthrust of the machine. Should'theendlong thrust decrease, the shaft pressure, p, in the space, C, andthusthe total pressure exercisedron the piston, a, toward the left,increases by the amount by I which the endlong thrust of the machine hasa that illustrated in Fig.

become less.

The form .of construction Without facings shown in Fig. 4 operatesexactl the same as 2 with t e sole difierenee that on motion of thepiston toward the right or the left, the specific pressures on the facesof the piston are not, constant, but

decrease according to a definite law.

Having thus described my invention, what faces adaplted to throttle thepressure agent the one of said-passages presentinga throt Through a Iclaim as new andfdesire to secure by Letters Patent is:-

1. An automatic balancing device, com

prising ashaft, a piston mounted thereon, a main pressure chamber, andva'chamber in which the piston works, with but throttlingclearanceat theperiphery and fissures at the on axial s ifting of the shaft 'in eitherdirec' tion, said iston-chamber communicating on the one si e with themain pressure chamber and on the other side with the atmosphere,

tiling-fissure concentric wlth the shaft, sub stantially as described} v7 2. An automatic balancing device, com'== prising a shaft, a pistonmounted thereon, a 1 main pressure chamber, and a chamber in which thepiston works with but throttlingclearance at the periphery and fissuresat the faces adapted to'throttle the pressure agent. on axial shiftingof the shaft in either direc tion, said piston chambercommunicating'on70 the oneside-wlth the mam ressure chamber by means of a throttlingssure concentric with the shaft and on the other side withtheatmosphere, substantially as described.

'3. automatic balancing device, comprising a shaft, a pistonmou ntedthereon, a

main pressure chamber, and a chamber in HENRY' HASPER, Hans Hangman.

the shaft, I

have signed my

